yasnippet-snippets VS ggtags

I second yasnippet, it is extremely handy for all sorts of boilerplate (like LaTeX preambles, environments). There are many contributed snippets in the yasnippet-snippets repo that you can look at as examples.

But you could look at what others do for Yasnippets? https://github.com/AndreaCrotti/yasnippet-snippets/tree/master/snippets/emacs-lisp-mode

You may want yasnippets. It's in melpa. I don't use lsp-mode. Consider using gnu global with ggtags and ctags for parsing and indexing your code-base for searching for symbols within emacs.

Can you access https://elpa.gnu.org in a browser?

The packages available via the built-in package manager once configured do not come from GitHub though they may be developed there. They come from GNU ELPA NonGNU ELPA and MELPA. You would still need internet access though.

To install elisp packages system-wide under the Portage control you can use gs-elpa. Read layman documentation before using it, as gs-elpa represents ELPA repositories as g-sorcery overlays. It currently supports 4 repositories: gnu-elpa, marmalade, melpa and melpa-stable.

I run emacs at work on a system that does not access the internet, so I cannot utilize the package interface that pulls directly from melpa (and elpa etc). Years ago, someone copied a version of melpa into a local directory on the air-gapped server. In my init.el, I setq package-archive to something like (("local-melpa" . "/path/to/the/melpa/dir")) so that it points to this local directory. I'm wondering if there is a tool to facilitate this sort of mirroring? I would like to update my packages on this air-gapped network. I am able to copy files onto the system from a less restricted workstation with internet access. Is it just a matter of unzipping the melpa repo and pointing package-archive to the fresh melpa directory?

https://github.com/leoliu/ggtags works well ; otherwise I use dumb-jump and eglot quite a bit

https://github.com/leoliu/ggtags can also be useful ; and for me ripgrep via https://github.com/leoliu/ack-el or https://github.com/jacktasia/dumb-jump

I get similar connection-security messages when attempting to connect to the package archive at https://elpa.nongnu.org/ —again, in both *Package* and in *eww*—while elpa.gnu.org seems to be just flat out nonresponsive. However, other https sites including https://duckduckgo.com/about and https://twitter.com work just fine.

I am working on adding more packages to NonGNU ELPA, the new package archive enabled by default from Emacs 28 onwards. Compared to GNU ELPA, there is no need for a copyright assignment (the only requirement is that packages do not endorse non-free software, but that is the case for most Emacs-related software to begin with).

You can also install the latest stable version of Org via GNU ELPA by invoking M-x package-install RET org RET.